Kidnapped. (A mild Tomco fanfic.)

Why would you steal a warnicorn?

"Why are they chasing us?" Marco yelled running along the cobbled streets. Fleeing from Mewni's equivalent of police.
"I don't know, I haven't done any...oh." Tom realised something and looked sheepish.
"What did you do."
"When we were twelve I stole a warnicorn for Star, I would've thought they would've forgotten about it by now. I mean. It was two years ago."
"On Mewni Warnicorns are rare! Star was telling me that if you kill a warnicorn then they catapult you and any witnesses into the distance. Please tell me you returned it!"
"Why would you steal something if you were going to bring it back?"
"I don't know. CONSCIENCE?!"
"I don't have a conscience, I'm a demon."
"Noted. What did You do with the Warnicorn?"
"You would've thought Warnicorns were fireproof. They are not."
"You set it on fire."
"Yes."
"So you killed it!"
"Well technically. I set it on fire. It jumped into the river and drowned itself."
Marco face palmed as they were running. "What now!" He yelled.
"Run into that wall."
"What?!"
"Trust me."
"Why would I trust you, you tried to kill me! twice!"
"Ugh mortals."
Tom grabbed Marco's hand and pushed him into a wall. He fell straight through it and face planted a puddle.
"Where are we?"
"West Mewni swamp. Get up."
Tom offered Marco a hand, he took it and Tom helped him up.
"You know, you're stronger than you look." Marco said loudly.
"Shut up." Tom whispered.
"No I'm being serious, like does it come from being a demon or..."
"Seriously be quiet."
"Why?"
Tom looked around in the dark, it smelt of damp. A musty smell. And somewhere in the distance there was the sound of water running. Tom gritted his teeth and leaned in close to Marco.
"Marco. Run."
"What?"
"Run. NOW!"
A shadow lunged out of the darkness pouncing onto Tom. Scratching at his, or technically Marco's, hoodie and fighting him. Marco ran off and hid silently behind a bush. Tom put up a good fight but descended into defeat when the creature tore his hand off. Then the creature dragged him, kicking, screaming and fighting into the darkness. Marco didn't know what that creature was but he sensed that there would be more nearby. So without hesitation he found the wall they had come through and walked straight through it.